Shock-absorbing device for net body of guard fence

ABSTRACT

There is provided a shock-absorbing device for a net body of a guard fence, capable of improving a net body&#39;s effectiveness of absorbing impact by enlarging the amount of deformation of the net body once the net body has been subjected to a force of impact due to rockfall, mudslide, avalanche or the like. A net body  4  has a net body turn-down portion  24  located on an edge portion thereof and formed by turning down oblique wire members  22  serving as wire members, and a net body intersecting portion  23  in which the oblique wire members  22  intersect with one another. The net body turn-down portion  24  or the net body intersecting portion  23  is linked, by means of a shock-absorbing rope member  40  and a shock-absorbing instrument  30,  to an upper transverse rope member  11  or a longitudinal rope member  52,  both of which serve as link receiving members of a guard fence  1.  Once the net body  4  has been subjected to an impact energy due to rockfall or the like, the shock-absorbing instrument  30  will friction slide along the shock-absorbing rope member  40  due to the net body turn-down portion  24  or the net body intersecting portion  23,  thereby absorbing the impact energy. In addition, the amount of deflection of the net body  4  becomes large as the shock-absorbing instrument  30  moves, thereby improving the effectiveness in absorbing the impact energy.

TECHNICAL FIELD

The present invention relates to a shock-absorbing device for a net bodyof a guard fence.

BACKGROUND ART

Conventionally, as one of the examples of a guard fence employing suchshock-absorbing device for net body, there has been known a guard fencecomprising: a concrete base provided on a boundary between an inclinedplane and a road; poles disposed on such concrete base at predeterminedintervals; and a guard net stretched between those poles in the form ofa band (e.g., see patent document 1)

Further there has been known a guard fence comprising: poles provided atpredetermined intervals; horizontal rope members provided between suchpoles; and a shock-absorbing portion formed in a mid section of thehorizontal rope member, in which a net made of wire is hooked on thehorizontal rope members so as to cover the space between the poles, andthe shock-absorbing portion comprises an extra length portion formed bybending the horizontal rope member in a mid section thereof and aclamping instrument for clamping the extra length portion with a certainamount of force (e.g., see patent document 2). Furthermore, there hasbeen known a guard fence in which transverse rods made of concrete,metal or the like are provided between the poles in the form of multiplerows. Furthermore, there has been known a guard fence in which analternate rope member is used to link an upper portion of the pole to aninclined plane in front of the pole, and a shock-absorbing instrumentfor slidably containing the alternate rope member is provided in a midsection of the alternate rope member (e.g., see patent document 3).

Furthermore, there has been known a guard fence in which transversesupporting ropes are provided between the poles, and an end portionholder is used to hold a turn-back portion of a net rope composing a netbody and the supporting rope so as to damp an impact energy (e.g., seepatent document 4).

REFERENCE

Patent document 1: Laid-open Japanese patent publication No. 2003-3425

Patent document 2: Laid-open Japanese patent publication No.Hei-6-173221

Patent document 3: Laid-open Japanese patent publication No. 2000-273827

Patent document 4: Laid-open Japanese patent publication No.Hei-7-252808

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

According to the guard fence disclosed in the patent document 4,although the net body is capable of absorbing a force of impact byfriction sliding, the amount of deformation of the net body as a wholeis small. By enlarging the amount of deformation of the net body, notonly the damping effect on the impact energy can be improved, but theamount of the force applied to the poles can also be reduced.

Therefore, it is an object of the present invention to provide ashock-absorbing device for net body of guard fence, capable of improvinga net body's effectiveness of absorbing an impact energy by enlargingthe amount of deformation of the net body when the net body has beensubjected to a force of impact due to rockfall, mudslide, avalanche andthe like.

Means for Solving the Problem

The present invention is for use in a guard fence comprising: polesvertically installed at intervals; a net body provided between thepoles; and a shock-absorbing instrument holding a shock-absorbing ropemember. The net body has a net body turn-down portion formed by turningdown wires on an edge portion thereof, and a net body intersectingportion in which the wires intersect with each other. By using theshock-absorbing rope member and the shock-absorbing instrument, the netbody turn-down portion or the net body intersecting portion can belinked to linkage members provided on the guard fence other than the netbody, and the shock-absorbing rope member is allowed to friction slidewith respect to the shock-absorbing instrument as the net body moves,thereby absorbing a force of impact applied to the net body.

Further, according to the present invention, a shock-absorbing turn-backloop is formed by allowing the shock-absorbing instrument to hold an endportion of a shock-absorbing turn-back portion formed by turning backthe shock-absorbing rope member. Such shock-absorbing turn-back loop islinked to the linkage member, and the net body turn-down portion or thenet body intersecting portion is fastened to the shock-absorbingturn-back loop.

Furthermore, according to the present invention, a loop portion isformed by curling back the shock-absorbing rope member toward itself,and the shock-absorbing instrument is used to hold a folded portion ofthe shock-absorbing rope member. The linkage member and theshock-absorbing turn-back portion or the net body intersecting portionare linked to each other by means of such loop portion.

Furthermore, according to the present invention, the shock-absorbingrope member is inserted through mesh patterns of a plurality of net bodyturn-down portions or net body intersecting portions, followed byturning back two end portions of such shock-absorbing rope member inopposite directions and allowing a turn-back portion to be fastened to alinkage portion of the guard fence. The end portions arranged inopposite directions are then laid one on top of another, and theshock-absorbing instrument is used to hold such overlapping portion.

Furthermore, according to the present invention, the shock-absorbingrope member is inserted through mesh patterns of a plurality of net bodyturn-down portions or net body intersecting portions. And, the linkagemember of the guard fence is provided with the shock-absorbinginstruments corresponding to the two end portions of the shock-absorbingrope member, respectively, thereby allowing the shock-absorbinginstruments on both ends to hold the two end portions of theshock-absorbing rope member, respectively.

Furthermore, according to the present invention, the linkage member is apair of linking rope members provided on the guard fence and distantfrom each other. A turning back portion formed by turning back a frontend portion of the shock-absorbing rope member is movably fastened toone and the other linking rope members of the pair of the linking ropemembers, respectively. The net body turn-down portion or the net bodyintersecting portion is linked to the front end portion, and an extralength portion is provided on the other side of the shock-absorbing ropemember. The extra length portions of one and the other shock-absorbingrope members are laid one on top of another, and the shock-absorbinginstrument is used to hold such overlapping portion.

Effects of the Invention

According to the aforementioned structure, once the net body has beensubjected to an impact energy due to rockfall or the like, theshock-absorbing instrument will friction slide along the shock-absorbingrope member as the net body turn-down portion or the net bodyintersecting portion moves, thereby absorbing the impact energy. Inaddition, the amount of deflection of the net body becomes large as theshock-absorbing instrument moves, thus making it possible to provide aguard fence superior in absorbing the impact energy effectively.

Further, since the net body turn-down portion or the net bodyintersecting portion is used for linking, the linking operation forlinking the net body to the guard fence becomes easy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear elevation showing a guard fence of an embodiment 1 ofthe present invention.

FIG. 2 is a rear elevation showing an essential portion of the guardfence of the embodiment 1 of the present invention.

FIG. 3 is a plan view showing the guard fence of the embodiment 1 of thepresent invention.

FIG. 4 is a side view showing the guard fence of the embodiment 1 of thepresent invention.

FIG. 5 is a front view showing an essential portion of a wire net of theguard fence of the embodiment 1 of the present invention.

FIG. 6 is a plan view showing a shock-absorbing instrument of the guardfence of the embodiment 1 of the present invention.

FIG. 7 is a rear elevation showing a shock-absorbing structure of theguard fence of the embodiment 1 of the present invention.

FIG. 8 is a front view showing a shackle of the guard fence of theembodiment 1 of the present invention.

FIG. 9 is a rear elevation showing an upper portion of a pole at one endof the guard fence of the embodiment 1 of the present invention.

FIG. 10 is a rear elevation showing a lower portion of the pole at oneend of the guard fence of the embodiment 1 of the present invention.

FIG. 11 is a side view showing the upper portion of the pole of theguard fence of the embodiment 1 of the present invention.

FIG. 12 is a side view showing the lower portion of the pole of theguard fence of the embodiment 1 of the present invention.

FIG. 13 is a side view showing the way an upper and a lower end portionsof a shock-absorbing rope member are turned back in opposite directionsaccording to the guard fence of the embodiment 1 of the presentinvention.

FIG. 14 is a rear elevation showing an upper portion of a pole in thecenter of the guard fence of the embodiment 1 of the present invention.

FIG. 15 is a rear elevation showing a lower portion of the pole in thecenter of the guard fence of the embodiment 1 of the present invention.

FIG. 16 is a plan view showing the pole at one end of the guard fence ofthe embodiment 1 of the present invention.

FIG. 17 is a plan view showing an essential portion of an alternate ropemember located at a side portion of the guard fence of the embodiment 1of the present invention.

FIG. 18 is a plan view showing the pole in the center of the guard fenceof the embodiment 1 of the present invention.

FIG. 19 is a front view showing a wire clip of the guard fence of theembodiment 1 of the present invention.

FIG. 20 is a rear elevation showing a shock-absorbing structure of anembodiment 2 of the present invention.

FIG. 21 is a rear elevation showing a shock-absorbing structure of anembodiment 3 of the present invention.

FIG. 22 is a rear elevation showing a shock-absorbing structure of anembodiment 4 of the present invention.

FIG. 23 is a rear elevation showing a shock-absorbing structure of anembodiment 5 of the present invention.

FIG. 24 is a rear elevation showing a shock-absorbing structure of anembodiment 6 of the present invention.

FIG. 25 is a rear elevation showing a shock-absorbing structure of anembodiment 7 of the present invention.

FIG. 26 is a front view showing an essential portion of a wire net of avariation of an embodiment 8 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferable embodiments of the present invention are described in detailwith reference to the accompanying drawings.

Embodiment 1

An embodiment 1 of the present invention is described hereunder withreference to FIG. 1 through FIG. 19. As shown in FIG. 1, a guard fence 1serving as a guard body for rockfall, avalanche, mudslide and the likehas a plurality of poles 3 vertically installed at predeterminedintervals on a concrete base 2 serving as an installation location.Between such poles 3 aligned in a left-right direction, there isprovided a flexible net body 4 serving as a guard surface. In addition,a steel pipe having a circular cross portion is employed as the pole 3in this embodiment.

On an upper and a lower portions of the poles 3, there are stretched anupper and a lower transverse rope members 11, 12, respectively. Further,on rear sides of the upper and lower portions of the poles 3, there arerespectively provided an upper and a lower fastening portions 13, 14 towhich the upper and lower transverse rope members 11, 12 are detachablyfastened. And, end portions of the upper and lower transverse ropemembers 11, 12 are linked to the fastening portions 13, 14 of the poles3, 3 at both ends.

However, no other transverse rope member is provided between the upperand lower transverse rope members 11, 12.

As shown in FIG. 5, the aforementioned net body 4 comprises a wire net21 composed of a plurality of oblique wire members 22, 22 intersectingwith one another, said oblique wire members 22, 22 being obtained bytwisting steel wires. Further, in a net body intersecting portion 23 ofthe oblique wire members 22, 22, one wire member 22 is intertwined withan other oblique wire member 22 in a manner such that the other obliquewire member 22 is inserted through the one oblique wire member 22. Withregard to the net body intersecting portions 23 adjacent to one anotherin a longitudinal direction of the oblique wire member 22, there arearranged alternately an intersecting portion 23 in which the otheroblique wire member 22 is inserted through the one oblique wire member22, and a net body intersecting portion 23 in which the one oblique wiremember 22 is inserted through the other oblique wire member 22. Inaddition, the one oblique wire member 22 of the wire net 21 is soarranged that it obliquely extends from upper left to lower right, andthe other oblique wire member 22 of the wire net 21 is so oppositelyarranged that it obliquely extends from upper right to lower left. Suchoblique wire members 22, 22 have a net body turn-down portion 24 turneddown at an angle of substantial 90 degrees on an edge of the net body 4,and the oblique wire members 22, 22 are continuous in the net bodyturn-down portion 24.

The diameter of the wire member 22 of the wire net 21 is 9 to 14 mm, andthe tension strength thereof is 30 to 90 kN. Further, a width Wcorresponding to a diagonal line of each mesh pattern of the wire net 21is 300 to 600 mm.

The wire net 21 is linked to the upper transverse rope member 11 servingas a linkage member by means of a shock-absorbing instrument 30 and ashock-absorbing rope member 40 made of a wire rope.

As shown in FIG. 6, in this case, the shock-absorbing instrument 30 iscomposed of two holding bodies 31, 31 and a clamping element 34including a U-bolt 32 for clamping, a screw nut 33 and the like. Twogrooves 35, 35 are formed on the holding bodies 31, 31, for containingthe shock-absorbing rope members 40, 40, respectively. Theshock-absorbing rope members 40, 40 are sandwiched by the holding bodies31, 31 from both sides so that the shock-absorbing rope members 40, 40can be contained by the grooves 35, 35. The U-bolt 32 is insertedthrough through-holes 36, 36 of the holding bodies 31, 31, followed byclamping such U-bolt 32 with the screw nut 33, thereby allowing theshock-absorbing rope members 40, 40 to be held therein. Further, theholding force (crimping force) applied to the shock-absorbing ropemembers 40, 40 can be adjusted in accordance with the clamping force ofthe U-bolt 32 and the screw nut 33. In addition, extra length portionsof the shock-absorbing rope members 40, 40 need to be formed so that atleast one of the shock-absorbing rope members 40, 40 is allowed toslide. Namely, end portions 40T, 40T of the shock-absorbing rope member40 are held by the U-bolt 32 and the screw nut 33 with a predeterminedfrictional force. But, when the tension force applied to the rope member40 exceeds a predetermined value as a force toppling the pole 3 isapplied thereto due to rockfall or the like, the shock-absorbing ropemembers 40, 40 are allowed to slide. In this way, since theshock-absorbing instrument 30 is provided, the shock-absorbing ropemembers 40, 40 are allowed to friction slide with respect to suchshock-absorbing instrument 30 when the tension force applied to theshock-absorbing rope member 40 by the wire net 21 exceeds apredetermined value, thereby effectively absorbing an impact energy.

As shown in FIG. 7, one shock-absorbing rope member 40 is bended into asubstantial “U” shape so as to form a shock-absorbing turn-back portion41. Further, shock-absorbing rope members 40, 40 serving as end portionsof such shock-absorbing turn-back portion 41 are held by theshock-absorbing instrument 30, thereby forming a shock-absorbingturn-back loop 42. In addition, the end portions 40T, 40T of theshock-absorbing rope member 40 are swaged with a metallic annular body,said metallic annular body combining the end portions 40T, 40T andserving as a stopper 43.

Also, the aforementioned net body turn-down portion 24 is insertedthrough the shock-absorbing turn-back loop 42, thereby allowing theshock-absorbing turn-back loop 42 to be fastened to the shock-absorbinginstrument 30. Further, the shock-absorbing turn-back loop 42 and theupper transverse rope member 11 are detachably linked to one another bya shackle 45 serving as a detachable linking means.

As shown in FIG. 8, the shackle 45 has a U-shaped main body 46 whose twoends can be opened and closed by means of a bolt 47 with a screw nutinserted therethrough. The shock-absorbing turn-back loop 42 and theupper transverse rope member 11 are inserted through the main body 46when it is closed, thereby linking the two together. Further, a portionof the shock-absorbing rope member 40 protruding away from theshock-absorbing turn-back loop 42 and the shock-absorbing instrument 30becomes an extra length portion 44 of the shock-absorbing rope member40.

Furthermore, on a lower edge of the wire net 21, the net body turn-downportion 24 and the lower transverse rope member 11 are linked togetherby means of the shackle 45. In addition, the wire net 21 is allowed tomove in the longitudinal directions of the transverse rope members 11,12and a longitudinal rope member described later by using the shackle 45.

Also, in this case, the shock-absorbing rope member 40 and theshock-absorbing instrument 30 compose a shock-absorbing structure 48.

As shown in FIG. 7, other than the upper transverse rope member 11, thelower transverse rope member 12 and the net body turn-down portion 24 ona lower side of the wire net 21 can also be linked together. Also, thelongitudinal rope member described later and the net body turn-downportion 24 on a left and a right edges of the wire net 21 can be linkedtogether as well. In this case, the lower transverse rope member 12 andthe longitudinal rope member serve as the linkage members. Further, ineither case, the net body intersecting portion 23 may be inserted intoand fastened to the shock-absorbing turn-back loop 42.

Next, as shown in FIG. 4 and other drawings, with regard to the pole 3,pin bolts 51, 51 serving as the linkage portions are transverselyinstalled in the aforementioned upper and lower fastening portions 13,14. And, a longitudinal rope member 52 serving as the linkage member isstretched between such upper and lower pin bolts 51, 51. In addition, aloop portion 52W is formed on an end portion of the longitudinal ropemember 52, for allowing the pin bolt 51 to be inserted therethrough.Although the number of the upper and lower transverse rope members 11,12 and the longitudinal as well as transverse rope members 52, 11, 12used is two, respectively, only one of each may be necessary.

In this case, the wire net 21 is so wide in the left-right directionthat the width thereof is substantially identical to an interval formedby the pole 3 in the center and the poles 3 at both ends. Further, thewire net 21 has the net body turn-down portion 24 located on both theleft and right edges thereof.

Furthermore, as shown in FIG. 9 through FIG. 12, with regard to thepoles 3 at both ends, one shock-absorbing rope member 40 is wound aroundthe longitudinal rope member 52 from the top downward while beingsuccessively inserted through and fastened to the net body turn-downportions 24 aligned longitudinally, from the top downward. Wheninserting the shock-absorbing rope member 40 through the mesh pattern ofthe wire net 21, a portion in which the shock-absorbing rope member 40is fastened to the net body turn-down portion 24 becomes a net bodyfastening portion 61. The shock-absorbing rope member 40 is insertedthough all the net body turn-down portions 24 located on the edges ofthe wire net 21. As shown in FIG. 13, the upper and lower end portions40T, 40T of the shock-absorbing rope member 40 are then respectivelyfastened to the upper and lower pin bolts 51, followed by turning backsuch end portions 40T, 40T upside down therefrom. A linkage memberfastening portion 62 at which the end portions 40T, 40T are turned backis fastened to the pin bolt 51. The end portions 40T, 40T thus turnedback in opposite directions are laid one on top of another, and theshock-absorbing instrument 30 is used to hold the portion in which theend portions 40T, 40T are thus laid one on top of another. Further, theend portions 40T, 40T protruding from the shock-absorbing instrument 30become the extra length portions 44.

Here, the longitudinal rope member 52 servers as a core member andallows the shock-absorbing rope member 40 to be stretched with apredetermined tension force.

Further, as shown in FIG. 14 and FIG. 15, with regard to the pole 3 inthe center, the net body turn-down portions 24, 24 are so arranged thatthey face one another across the longitudinal rope member 52 in theleft-right direction. A shock-absorbing rope member 40 is wound aroundthe longitudinal rope member 52 from the top downward while beingsuccessively inserted through and fastened to the net body turn-downportions 24 aligned longitudinally, from the top downward. Morespecifically, the shock-absorbing rope member 40 is inserted through andfastened to both a left and a right net body turn-down portions 24 perrow. A portion in which the shock-absorbing rope member 40 is fastenedto the net body turn-down portion 24 becomes the net body fasteningportion 61. Both a left and a right net body fastening portions 61, 61in each row are positioned substantially at the same height. Theshock-absorbing rope member 40 is inserted though all the left and rightnet body turn-down portions 24 across the pole 3. The upper and lowerend portions of the shock-absorbing rope member 40 are then respectivelyfastened to the upper and lower pin bolts 51, followed by turning backsuch end portions upside down therefrom. The linkage member fasteningportion 62 at which such end portions are turned back is fastened to thepin bolt 51. The end portions 40T, 40T thus turned back in oppositedirections are laid one on top of another, and the shock-absorbinginstrument 30 is used to hold the portion in which the end portions 40T,40T are thus laid one on top of another. Further, the end portions 40T,40T protruding from the shock-absorbing instrument 30 become the extralength portions 44, 44.

Further, on an outward side of the left-right direction of the poles 3at both ends, an alternate rope member linking portion 72 is fixed on anupper surface of the aforementioned concrete base 2 by means of ananchor 71. Such alternate rope member linking portion 72 is linked tothe corresponding upper portions of the poles 3 at both ends by analternate rope member 73.

In addition, an anchor 74 is buried in an inclined plane which is aground surface in front (mountain side) of all the poles 3. Such anchor74 is linked to the upper portion of the pole 3 by an alternate ropemember 75. In this case, a round bar 76 serving as a fastening portionis inserted through the upper portion of the pole 3 in a manner suchthat end portions thereof protrude from the pole 3 toward the left-rightdirection. The alternate rope member 75 is so wound around the pole 3that it is fastened to upper sides of the two end portions of the roundbar 76. And then, a superposition portion 75K of the alternate ropemember 75 thus wound is bound by a wire clip 77 serving as a bindingmeans, in front of the pole 3. In this way, the alternate rope member 75is allowed to be linked to the upper portion of the pole 3.

Further, as shown in FIG. 19, the wire clip 77 is composed of a U-bolt78 and a main body 79 for inserting such U-bolt 78 therethrough. Thewire clip 77 sandwiches the superposition portion 75K between the U-bolt78 and the main body 79.

Operation regarding the abovementioned structure is described hereunder.With regard to the upper transverse rope member 11, once the net body 4has been subjected to a force of impact due to rockfall, mudslide,avalanche and the like, a tension force will be generated on the wirenet 21, and a force pulling the net body turn-down portion 24 downwardwill also be applied to the wire net 21. Therefore, the shock-absorbinginstrument 30 to which the net body turn-down portion 24 is fastenedwill friction slide along the extra length portion 44, and thus absorbthe force of impact. Further, the amount of deflection of the wire net21 becomes large as the shock-absorbing instrument 30 moves, therebyimproving the effectiveness of absorbing the force of impact, and thusreducing the force applied to the pole 3 or the like.

Further, once the shock-absorbing instrument 30 has come into contactwith the stopper 43 after friction sliding along the extra lengthportion 44, the shock-absorbing instrument 30 will stop frictionsliding. Therefore, the force of impact is then absorbed by virtue ofthe tension force of the shock-absorbing rope member 40.

Further, with regard to the poles 3 at both ends, once the net body 4has been subjected to a force of impact due to rockfall, mudslide,avalanche and the like, a tension force will be generated on the wirenet 21, and a force pulling the net body turn-down portion 24 toward thecenter will also be applied to the wire net 21. In this way, a tensionforce will be applied to the shock-absorbing rope member 40 to which thenet body turn-down portion 24 is fastened, and the shock-absorbing ropemember 40 having a loop-like shape as a whole will be subjected to thetension force, thereby allowing the extra length portions 44, 44 servingas the end portions to friction slide with respect to theshock-absorbing instrument 30, and thus allowing the force of impact tobe absorbed. In addition, as the shock-absorbing rope member 40 having aloop-like shape as a whole is enlarged, the amount of deflection of thewire net 21 becomes large, thereby improving the effectiveness ofabsorbing the force of impact, and thus reducing the force applied tothe pole 3 or the like.

Similarly, with regard to the pole 3 in the center, once the net body 4has been subjected to a force of impact due to rockfall, mudslide,avalanche and the like, a tension force will be generated on the wirenets 21, 21 located on both sides of the pole 3. Namely, a force tryingto pull the net body turn-down portion 24 away from the pole 3 will beapplied to the wire nets 21, 21, thereby applying a tension force to theshock-absorbing rope member 40 to which the net body turn-down portion24 is fastened, and thus applying the tension force to theshock-absorbing rope member 40 having a loop-like shape as a whole. Inthis way, the extra length portions 44, 44 serving as the end portionsare allowed to friction slide with respect to the shock-absorbinginstrument 30, thereby allowing the force of impact to be absorbed.Further, as the shock-absorbing rope member 40 having a loop-like shapeas a whole is enlarged, the amount of deflection of the wire nets 21, 21located on both sides becomes large, thereby improving the effectivenessof absorbing the force of impact, and thus reducing the force applied tothe pole 3 or the like. In addition, with regard to the pole 3 in thecenter, when one of a left and a right wire nets 21 has been subjectedto the force of impact, such force of impact will be transmitted to theother wire net 21 by virtue of the shock-absorbing rope member 40,thereby distributing the force of impact.

In this sense, the present embodiment is suitable for use in the guardfence comprising poles 3, 3 vertically installed at the predeterminedintervals, the net body 4 provided between the poles 3, 3 and theshock-absorbing instrument 30 holding the shock-absorbing rope member40. The net body 4 has the net body turn-down portion 24 on an edgeportion thereof, in which the oblique wire member 22 serving as a wiremember is turned down, and the net body intersecting portion 23 in whichthe oblique wire members 22 intersect with one another. By using theshock-absorbing rope member 40 and the shock-absorbing instrument 30,the net body turn-down portion 24 or the net body intersecting portion23 can be linked to the upper transverse rope member 11 or thelongitudinal rope member 52 other than the net body 4, both of whichserve as the linkage members provided on the guard fence 1. Theshock-absorbing rope member 40 slides with respect to theshock-absorbing instrument 30 as the net body 4 moves, thereby absorbinga force of impact applied to the net body 4. Namely, once an impactenergy due to rockfall and the like has been applied to the net body 4,the shock-absorbing instrument 30 will friction slide along theshock-absorbing rope member 40 due to the net body turn-down portion 24or the net body intersecting portion 23 so as to absorb the impactenergy. In addition, the amount of deflection of the net body 4 becomeslarge as the shock-absorbing instrument 30 moves, thereby improving theeffectiveness of absorbing the impact energy.

Further, according to the present embodiment, the shock-absorbingturn-back loop 42 is formed by allowing the shock-absorbing instrument30 to hold the end portion of the shock-absorbing turn-back portion 41formed by turning back the shock-absorbing rope member 40. Theshock-absorbing turn-back loop 42 is linked to the upper transverse ropemember 11 serving as the linkage member, and the net body turn-downportion 24 or the net body intersecting portion 23 is fastened to suchshock-absorbing turn-back loop 42. Therefore, once an impact energy dueto rockfall or the like has been applied to the net body 4, theshock-absorbing instrument 30 will friction slide along theshock-absorbing rope member 40 due to the net body turn-down portion 24or the net body intersecting portion 23 fastened to the shock-absorbinginstrument 30, thereby absorbing the impact energy. In addition, theamount of deflection of the net body 4 becomes large as theshock-absorbing instrument 30 moves, thereby improving the effectivenessof absorbing the impact energy.

Furthermore, according to the present embodiment, the net body turn-downportion 24 or the net body intersecting portion 23 is inserted into andfastened to the shock-absorbing turn-back loop 42, thereby allowing thenet body turn-down portion 24 or the net body intersecting portion 23 tobe fastened to the shock-absorbing instrument 30, thud obtaining ashock-absorbing device with a simple structure.

Furthermore, according to the present embodiment, the shock-absorbingrope member 40 is inserted through a plurality of the mesh patterns ofthe net body turn-down portions 24 or the net body intersecting portions23. The two end portions 40T, 40T of the shock-absorbing rope member 40are turned back in opposite directions, and the portions at which thetwo end portions 40T, 40T are thus turned back are fastened to the pinbolts 51, 51 serving as the linkage portions of the guard fence 1. Suchend portions 40T, 40T in opposite directions are laid one on top ofanother, and the shock-absorbing instrument 30 is used to hold theportion in which the end portions 40T, 40T are thus laid one on top ofanother. Therefore, once an impact energy due to rockfall or the likehas been applied to the net body 4, a tension force will be applied tothe shock-absorbing rope member 40 inserted through a plurality of themesh patterns of the net body turn-down portions 24 or the net bodyintersecting portions 23. Thus, the end portions 40T, 40T of theshock-absorbing rope member 40 are allowed to friction slide withrespect to the shock-absorbing instrument 30 so as to absorb the impactenergy, said shock-absorbing instrument 30 holding the portion in whichthe two end portions 40T, 40T are laid one on top of another. Inaddition, the amount of deflection of the net body 4 can become large asthe shock-absorbing rope member 40 friction slides, thereby improvingthe effectiveness of absorbing the impact energy.

Furthermore, as an effect of the present embodiment, the shock-absorbingrope member 40 is fastened to a plurality of the net body turn-downportions 24 on the edge of the wire net 21, thereby allowing the edge ofthe wire net 21 to be linked to the pole 3 with one shock-absorbing ropemember 40.

Embodiment 2

An embodiment 2 of the present invention is shown in FIG. 20. Samereference numbers are used to describe the same members as those in theaforementioned embodiment 1, thereby omitting the detailed descriptionsof such members when describing the embodiment 2. As shown in FIG. 20,one shock-absorbing rope member 40 is bended into a substantial “U”shape so as to form the shock-absorbing turn-back portion 41. Further,the shock-absorbing rope members 40, 40 serving as the end portions ofsuch shock-absorbing turn-back portion 41 are held by theshock-absorbing instrument 30, thereby forming the shock-absorbingturn-back loop 42. In addition, the end portions 40T, 40T of theshock-absorbing rope member 40 are respectively swaged with the metallicannular bodies serving as the stoppers 43, 43. One of the end portions40T has an extra length portion 44, and the stopper 43 of the other endportion 40T is positioned in the vicinity of the shock-absorbinginstrument 30.

In addition, other than the upper transverse rope member 11, the lowertransverse rope member 12 and the net body turn-down portion 24 on alower end of the wire net 21 can be linked together. Also, thelongitudinal rope member 52 and the net body turn-down portion 24 oneither the left or right edge of the wire net 21 can be linked togetheras well. In this case, the lower transverse rope member 12 and thelongitudinal rope member serve as the linkage members. Further, the netbody intersecting portion 23 may be inserted into and fastened to theshock-absorbing turn-back loop 42.

And then, once the wire net 21 has been subjected to a force of impact,and a force stronger than a predetermined force has been applied to theshock-absorbing instrument 30 by the net body turn-down portion 24, oneextra length portion 44 will friction slide with respect to theshock-absorbing instrument 30 so as to absorb the force of impact, andthe wire net 21 will move away from the upper transverse rope member 11as the shock-absorbing instrument 30 moves. Therefore, the amount ofdeformation of the net body 4 becomes large, thus absorbing the force ofimpact also.

Further, in this case, the one extra length portion 44 slides withrespect to the shock-absorbing instrument 30 and friction slides withrespect to the main body 46 of the shackle 45 at the same time, therebymaking it possible to partially absorb the force of impact even with thefriction slide taken place between the extra length portion 44 and themain body 46.

Embodiment 3

An embodiment 3 of the present invention is shown in FIG. 21. Samereference numbers are used to describe the same members as those in theaforementioned embodiments, thereby omitting the detailed descriptionsof such members when describing the embodiment 3. As shown in FIG. 21and according to the present embodiment while referring to theembodiment 1, an openable hook 81 serving as the fastening portion isprovided on the shock-absorbing instrument 30, and the net bodyturn-down portion 24 is inserted into and fastened to such openable hook81. Here, a U-bolt that can be detachably attached to theshock-absorbing instrument 30 is employed as the openable hook 81.

In addition, other than the upper transverse rope member 11, the lowertransverse rope member 12 and the net body turn-down portion 24 on thelower end of the wire net 21 can be linked together. Also, thelongitudinal rope member 52 and the net body turn-down portion 24 oneither the left or right edge of the wire net 21 can be linked togetheras well. In this case, the lower transverse rope member 12 and thelongitudinal rope member serve as the linkage members. Further, the netbody intersecting portion 23 may be inserted into and fastened to theopenable hook 81. Furthermore, the openable hook 81 is provided on theshock-absorbing instrument 30 in the embodiment 2, and the net bodyturn-down portion 24 or the net body intersecting portion 23 may befastened to such openable hook 81.

And then, once the wire net 21 has been subjected to a force of impact,and a force stronger than a predetermined force has been applied to theshock-absorbing instrument 30 by the net body turn-down portion 24, theextra length portions 44, 44 will friction slide with respect to theshock-absorbing instrument 30 so as to absorb the force of impact, andthe wire net 21 will move away from the upper transverse rope member 11as the shock-absorbing instrument 30 moves. Therefore, the amount ofdeformation of the wire net 21 becomes large, thus absorbing the forceof impact also.

Further, according to the present embodiment, the openable hook 81serving as the fastening portion is provided on the shock-absorbinginstrument 30 for allowing the net body turn-down portion 24 or the netbody intersecting portion 23 to be fastened thereto. In this sense, thenet body turn-down portion 24 or the net body intersecting portion 23can be fastened to the shock-absorbing instrument 30 and theshock-absorbing turn-back loop 42 by means of such openable hook 81,thereby obtaining a shock-absorbing device with a simple structure.

Embodiment 4

An embodiment 4 of the present invention is shown in FIG. 22. Samereference numbers are used to describe the same members as those in theaforementioned embodiments, thereby omitting the detailed descriptionsof such members when describing the embodiment 4. As shown in FIG. 22and according to the present embodiment, a shock-absorbing loop 63 isformed by curling one shock-absorbing rope member 40 in a midsectionthereof, and the net body turn-down portion 24 is inserted into andfastened to the shock-absorbing loop 63. Further, such shock-absorbingloop 63 and the upper transverse rope member 11 are linked to oneanother by the shackle 45.

In addition, other than the upper transverse rope member 11, the lowertransverse rope member 12 and the net body turn-down portion 24 on thelower end of the wire net 21 can be linked together. Also, thelongitudinal rope member 52 and the net body turn-down portion 24 oneither the left or right edge of the wire net 21 can be linked togetheras well. In this case, the lower transverse rope member 12 and thelongitudinal rope member 52 serve as the linkage members.

And then, once the wire net 21 has been subjected to a force of impact,and a force stronger than a predetermined force has been applied to theshock-absorbing loop 63 by the net body turn-down portion 24, the extralength portions 44, 44 in opposite directions will friction slide withrespect to the shock-absorbing instrument 30 so as to absorb the forceof impact, and the wire net 21 will move away from the upper transverserope member 11 as the shock-absorbing loop 63 enlarges due to thefriction slide of the extra length portions 44, 44. Therefore, theamount of deformation of the wire net 21 becomes large, thus absorbingthe force of impact also.

Further, according to the present embodiment, the shock-absorbing loop63 serving as a loop portion is formed by curling the shock-absorbingrope member 40, and the shock-absorbing instrument 30 is used to holdthe portion in which the shock-absorbing rope member 40 is folded,thereby allowing the upper transverse rope member 11 and theshock-absorbing turn-back portion 24 or the net body intersectingportion 23 to be linked together by means of the shock-absorbing loop63. Therefore, once an impact energy due to rockfall or the like hasbeen applied to the net body 4, the shock-absorbing loop 63 linked tothe upper transverse rope member 11 and the net body turn-down portion24 or the net body intersecting portion 23 will be subjected to a forcetrying to enlarge the shock-absorbing loop 63 itself. Thus, theshock-absorbing instrument 30 is allowed to friction slide with respectto the shock-absorbing rope member 40 so as to absorb the impact energy.In addition, the amount of deflection of the net body 4 can become largeas the shock-absorbing loop 63 enlarges, thereby improving theeffectiveness of absorbing the impact energy.

Further, according to the present embodiment, the shock-absorbingturn-back portion 24 and or the net body intersecting portion 23 isinserted though the shock-absorbing loop 63 serving as the loop portion.In this sense, the net body turn-down portion 24 or the net bodyintersecting portion 23 can be linked to the shock-absorbing loop 63 byallowing the net body turn-down portion 24 or the net body intersectingportion 23 to be inserted thereinto, thereby obtaining a shock-absorbingdevice with a simple structure.

Further, as an effect of the present embodiment, the upper transverserope member 11 serving as the linkage member can be inserted through theshock-absorbing loop 63, thereby allowing the shock-absorbing structure48 to be easily attached to the linkage member.

Embodiment 5

An embodiment 5 of the present invention is shown in FIG. 23. Samereference numbers are used to describe the same members as those in theaforementioned embodiments, thereby omitting the detailed descriptionsof such members when describing the embodiment 5. As shown in FIG. 23,with regard to the pole 3 in the center in which the wire net 21 iscontinuous in the left-right direction, one shock-absorbing rope member40 is fastened to multiple rows of net body intersecting portions 23located on the rear side of the pole 3 in the center. Theshock-absorbing rope member 40 is successively inserted through andfastened to the net body intersecting portions 23 arranged in thelongitudinal direction, from the top down ward. More specifically, theshock-absorbing rope member 40 is introduced from a mesh pattern on oneof a right and a left sides to one of a front and a rear sides, followedby passing such shock-absorbing rope member 40 through a mesh pattern onthe other right or left side to the other front or rear side. Theportion in which the shock-absorbing rope member 40 is fastened to thenet body intersecting portion 23 becomes the net body fastening portion61. In this manner, the shock-absorbing rope member 40 is furtherfastened to the net body intersecting portions 23 in the following rowsaligned next to each other longitudinally, and is thus fastened to allthe net body intersecting portions 23 by repeating this procedure. Theupper and lower end portions of the shock-absorbing rope member 40 arethen respectively fastened to the upper and lower pin bolts 51, followedby turning back such end portions 40T, 40T upside down therefrom. Thelinkage member fastening portion 62 at which the end portions are thusturned back is fastened to the pin bolt 51. The end portions 40T, 40Tturned back in opposite directions are laid one on top of another, andthe shock-absorbing instrument 30 is used to hold the portion in whichthe end portions 40T, 40T are thus laid one on top of another.

Further, the end portions 40T, 40T protruding from the shock-absorbinginstrument 30 become the extra length portions 44. In addition, in thiscase, the shock-absorbing rope member 40 and a pair of shock-absorbinginstruments 30, 30 compose the shock-absorbing structure 48.

According to FIG. 23, the shock-absorbing rope member 40 is fastened tothe net body intersecting portion 23 in a manner such that theshock-absorbing rope member 40 is introduced from a mesh pattern on theleft side from the back to front, and then inserted through a meshpattern on the right side from the front to back.

And then, once the wire net 21 located on one of the left and rightsides of the pole 3 in the center has been subjected to a force ofimpact, and a force stronger than a predetermined force has been appliedto the shock-absorbing loop 63 by the net body turn-down portion 24, theextra length portions 44, 44 in opposite directions will friction slidewith respect to the shock-absorbing instrument 30 so as to absorb theforce of impact, and the shock-absorbing rope member 40 having aloop-like shape as a whole will become large as the extra lengthportions 44, 44 friction slide, thereby causing the wire net 21 to moveto a side thereof which has been subjected to the force of impact. Inthis sense, the amount of deformation of the wire net 21 becomes large,thus absorbing the force of impact also.

Furthermore, according to the present embodiment, the shock-absorbingrope member 40 is inserted through a plurality of the mesh patterns ofthe net body turn-down portions 24 or the net body intersecting portions23. The two end portions of the shock-absorbing rope member 40 areturned back in opposite directions, and the portions in which the twoend portions 40T, 40T are thus turned back are fastened to the pin bolts51, 51 serving as the linkage portions of the guard fence 1. Such endportions 40T, 40T in opposite directions are laid one on top of another,and the shock-absorbing instrument 30 is used to hold the portion inwhich the end portions 40T, 40T are thus laid one on top of another.Therefore, once an impact energy due to rockfall or the like has beenapplied to the net body 4, a tension force will be applied to theshock-absorbing rope member 40 inserted through a plurality of the meshpatterns of the net body turn-down portions 24 or the net bodyintersecting portions 23. Thus, the end portions 40T, 40T of theshock-absorbing rope member 40 are allowed to friction slide withrespect to the shock-absorbing instrument 30 so as to absorb the impactenergy, said shock-absorbing instrument 30 holding the portion in whichthe two end portions 40T, 40T are laid one on top of another. Inaddition, the amount of deflection of the net body 4 can become large asthe shock-absorbing rope member 40 friction slides, thereby improvingthe effectiveness of absorbing the impact energy.

Embodiment 6

An embodiment 6 of the present invention is shown in FIG. 24. Samereference numbers are used to describe the same members as those in theaforementioned embodiments, thereby omitting the detailed descriptionsof such members when describing the embodiment 6. As shown in FIG. 24,the longitudinal rope member 52 is longitudinally provided on the rearside of the pole 3 at both ends, and a shock-absorbing rope member 40 iswound around the longitudinal rope member 52 from the top downward whilebeing successively inserted through and fastened to the net bodyturn-down portions 24 aligned longitudinally, from the top downward.When inserting the shock-absorbing rope member 40 through the meshpattern of the wire net 21, a portion in which the shock-absorbing ropemember 40 is fastened to the net body turn-down portion 24 becomes thenet body fastening portion 61. The shock-absorbing rope member 40 isinserted though all the mesh patterns of the net body turn-down portions24 located on the edge of the wire net 21, and the end portions of theshock-absorbing rope member 40 serve as an upper and a lower extralength portions 44, 44 longitudinally extending away from each otherwith respect to the pole 3.

Further, short auxiliary rope members 82, 82 are linked to the upper andlower pin bolts 51, 51, respectively, in a manner such that theauxiliary rope member 82 is held by one of the grooves 35 of theshock-absorbing instrument 30. And, a stopper 83 fastened to theshock-absorbing instrument 30 is provided on an end portion of suchauxiliary rope member 82. The extra length portion 44 is then held bythe other groove 35 of the shock-absorbing instrument 30, thus allowingthe shock-absorbing rope member 40 to be stretched on the rear side ofthe pole 3.

In addition, the shock-absorbing rope member 40 may also be fastened toan upper and a lower net body turn-down portions 24 or net bodyintersecting portions 23 while being wound around the upper and lowertransverse rope members 11, 12, instead of the longitudinal rope member52.

And then, once the wire net 21 has been subjected to a force of impact,and a force stronger than a predetermined force has been applied to theshock-absorbing rope member 40 by the net body turn-down portion 24, atleast one of the upper and lower extra length portions 44, 44 willfriction slide with respect to the shock-absorbing instruments 30, 30 soas to absorb the force of impact, and the shock-absorbing rope member 40between the shock-absorbing instruments 30, 30 will stretch as the extralength portions 44, 44 friction slide, thereby allowing the wire net 21to move away from the longitudinal rope member 52. In this sense, theamount of deformation of the wire net 21 becomes large, thus absorbingthe force of impact also.

Furthermore, according to the present embodiment, the shock-absorbingrope member 40 is inserted through a plurality of the mesh patterns ofthe net body turn-down portions 24 or the net body intersecting portions23. The pin bolts 51, 51 serving as the linkage portions of the guardfence 1 are respectively provided with the shock-absorbing instruments30, 30 corresponding to the two end portions 40T, 40T of theshock-absorbing rope member 40. Such shock-absorbing instruments 30, 30on both sides are used to hold the two end portions 40T, 40T of theshock-absorbing rope member 40, respectively. Therefore, once an impactenergy due to rockfall or the like has been applied to the net body 4, atension force will be applied to the shock-absorbing rope member 40inserted through a plurality of the mesh patterns of the net bodyturn-down portions 24 or the net body intersecting portions 23. Thus, atleast one of the end portions 40T, 40T of the shock-absorbing ropemembers 40, 40 is allowed to friction slide with respect to theshock-absorbing instruments 30, 30 holding the two end portions 40T,40T, thereby absorbing the impact energy. In addition, the amount ofdeflection of the net body 4 can become large as the shock-absorbingrope member 40 friction slides, thereby improving the effectiveness ofabsorbing the impact energy.

Furthermore, as an effect of the present embodiment, two shock-absorbinginstruments 30, 30 are used to hold one shock-absorbing rope member 40,thereby improving the effectiveness of shock absorbing.

Embodiment 7

An embodiment 7 of the present invention is shown in FIG. 25. Samereference numbers are used to describe the same members as those in theaforementioned embodiments, thereby omitting the detailed descriptionsof such members when describing the embodiment 7. As shown in FIG. 25,the present embodiment uses the upper and lower transverse rope members11, 12 serving as a pair of rope members distant from each other, andtwo shock-absorbing rope members 40, 40. A linking loop 84 is integrallyformed on one end of the shock-absorbing rope member 40. The end portionof the shock-absorbing rope member 40 is inserted through theaforementioned shackle 45 with a front end of the linking loop 84pointing to the center, followed by positioning the extra length portion44 of the end portion toward the center, thereby allowing a turn-backportion 40K of the shock-absorbing rope member 40 to be fastened to theshackle 45. Further, when using two pairs of the shock-absorbing ropemember 40 and the shackle 45, one of the shackles 45 is linked to theupper transverse rope member 11, while the other shackle 45 is linked tothe lower transverse rope member 12. In addition, the extra lengthportions 44, 44 of one and the other shock-absorbing rope members 40, 40are laid one on top of another in a midsection thereof, and theshock-absorbing instrument 30 is then used to hold the rope members 40,40, specifically the portion in which the extra length portions 44, 44are laid one on top of another. In addition, according to FIG. 25, thelinking loop 84 and the mesh pattern of the net body turn-down portion24 are linked to each other.

Further, the shock-absorbing structure 48 is composed of a pair of theshock-absorbing rope members 40, 40, a pair of the shock-absorbinginstruments 30, 30 and a pair of the loops 84, 84.

In addition, the longitudinal rope members 52, 52 provided on the poles3, 3 may be used as a pair of the rope members distant from each other.And, pairs of the shackles 45, 45 can be provided on both longitudinalrope members 52, 52 in the form of multiple rows. In this way, pairs ofthe shock-absorbing rope members 40, 40 are then stretched between thepoles 3, 3, and provided as transverse rope members and in the form ofmultiple rows between the upper and lower transverse rope members 11,12.

And then, once the wire net 21 has been subjected to a force of impact,and a force trying to pull the loop 84 of the shock-absorbing ropemember 40 toward the center has been applied by the net body turn-downportion 24, at least one of the upper and the lower extra lengthportions 44, 44 will friction slide with respect to the shock-absorbinginstruments 30, 30 by moving outward, thereby absorbing the force ofimpact. In addition, the shock-absorbing rope member 40 between theshock-absorbing instruments 30, 30 will stretch as the extra lengthportions 44, 44 friction slide, thereby allowing the wire net 21 to moveaway from the upper and lower transverse rope members 11, 12. In thissense, the amount of deformation of the wire net 21 becomes large, thusabsorbing the force of impact also.

Further, according to the present embodiment, the linkage member is apair of linking rope members provided on the guard fence 1.Specifically, the upper and lower rope members 11, 12 serve as the pairof the linking rope members, and are so arranged that they are distantfrom each other. The turn-back portion 40K formed by turning back afront end portion of the shock-absorbing rope member 40 is movablyfastened to the upper and lower transverse rope members 11, 12,respectively, said upper and lower transverse rope members 11, 12 beingprovided as a pair and serving as one and the other linking members. Thenet body turn-down portion 24 or the net body intersecting portion 23 islinked to the linking loop 84 formed on the front end portion, and theextra length portion 44 is provided on the other side of theshock-absorbing rope member 40. The extra length portions 44, 44 of oneand the other shock-absorbing rope members 40, 40 are then laid one ontop of another, and the shock-absorbing instrument 30 is used to holdthe portion in which the extra length portions 44, 44 are thus laid oneon top of another. Therefore, once an impact energy due to rockfall orthe like has been applied to the net body, a tension force working inone direction will be applied to the linking loop 84 formed on the frontend portion of the shock-absorbing rope member 40, said linking loop 84being linked to a plurality of the net body turn-down portions 24 or thenet body intersecting portions 23. Thus, a tension force trying to pullthe extra length portion 44 in a direction opposite to theaforementioned one direction will be generated, thereby allowing theextra length portion 44 to friction slide with respect to theshock-absorbing instrument 30, and thus absorbing the impact energy. Inaddition, the amount of deflection of the net body 4 can become large asthe shock-absorbing rope member 40 friction slides, thereby improvingthe effectiveness of absorbing the impact energy.

Furthermore, as an effect of the present embodiment, the linking loop 84is provided on the front end portion of the shock-absorbing rope member40, thereby making it easier to link the linking loop 84 to the net bodyturn-down portion 24 or the net body intersecting portion 23 throughinsertion.

Embodiment 8

An embodiment 8 of the present invention is shown in FIG. 26. Samereference numbers are used to describe the same members as those in theaforementioned embodiments, thereby omitting the detailed descriptionsof such members when describing the embodiment 8. According to the wirenet 21 shown in FIG. 26, intersection linking wire members 91, 92 areprovided on the net body intersecting portion 23 of the oblique wiremembers 22, 22. Fixing portions 91K, 91K are then formed on both sidesof the one oblique wire member 22 across the intersecting portion 23 bywinding both ends of one intersection linking wire members 91therearound coilwise. Such fixing portions 91K, 91K are continuous witheach other through a center portion 91C of the intersection linking wiremember 91. Fixing portions 92K, 92K are then formed on both sides of theother oblique wire member 22 across the intersection point by windingboth ends of the other intersection linking wire members 92 therearoundcoilwise. Such fixing portions 92K, 92K are continuous with each otherthrough a center portion 92C of the intersection linking wire member 92.Once a force trying to move the intersecting portion has been applied,the corresponding intersection linking wire members 91, 92 will actagainst it.

Further, various types of linking structures can be employed as thelinking structures for the net body intersecting portion 23 of the wirenet 21.

However, the present invention is not limited to the aforementionedembodiments, and various modified embodiments are possible. For example,net bodies with various shapes can be employed as the net body. Further,although a pole having a circular cross portion is employed according tothe embodiments, a pole having a rectangular cross portion can also beemployed. Further, various detachable linking means other than theshackle can be employed for movably linking the net body to the upperedge and lower edge rope members, as long as they have a loop forinserting a rope member or the like therethrough. Further, although ropemembers made of steel are employed according to the embodiments, ropemembers made of other materials such as synthetic resin or the like canalso be employed. Further, the number of the poles in the center can betwo or more. Further, the stopper can actually be provided on the endportion of the shock-absorbing rope member even with the embodiments inwhich the stopper is not shown. Further, all the rope members employedin the present invention are flexible. Further, according to theembodiments, the upper and lower transverse rope members and thelongitudinal rope member are employed as the linkage members. However,an upper and lower transverse rods made of a hard material and stretchedbetween the upper portions or lower portions of the pole may also beemployed as the linkage members, instead of the upper and lowertransverse rope members. Also, a longitudinal rod made of a hardmaterial and longitudinally provided on the pole may be employed as thelinkage member, instead of the longitudinal rope member. Various membersprovided on the guard fence other than the net body can be used as thelinkage members. Further, an auxiliary net made of a thin wire memberand having smaller mesh patterns than those of the wire net can besuperimposed on the wire net.

1. A shock-absorbing device for a net body of a guard, said guard fencecomprising: poles vertically installed at intervals; a net body providedbetween said poles; and a shock-absorbing instrument holding ashock-absorbing rope member, wherein said net body has a net bodyturn-down portion formed by turning down_wire members on an edge portionthereof, and a net body intersecting portion in which said wire membersintersect with each other, said net body turn-down portion or said netbody intersecting portion being linked to a linkage member provided onsaid guard fence other than said net body, using said shock-absorbingrope member and said shock-absorbing instrument, so that saidshock-absorbing rope member is allowed to friction slide with respect tosaid shock-absorbing instrument as said net body moves, therebyabsorbing a force of impact applied to said net body, and wherein ashock-absorbing turn-back loop is formed by allowing saidshock-absorbing instrument to hold an end portion of a shock-absorbingturn-back portion formed by turning back said shock-absorbing ropemember, said shock-absorbing turn-back loop being linked to said linkagemember, while said net body turn-down portion or said net bodyintersecting portion being fastened to said shock-absorbing turn-backloop.
 2. The shock-absorbing device for a net body of a guard fenceaccording to claim 1, wherein said net body turn-down portion or saidnet body intersecting portion is inserted through and fastened to saidshock-absorbing turn-back loop.
 3. The shock-absorbing device for a netbody of a guard fence according to claim 1, wherein said shock-absorbinginstrument is provided with a fastening portion to which said net bodyturn-down portion or said net body intersecting portion is fastened. 4.A shock-absorbing device for a net body of a guard fence, said guardfence comprising: poles vertically installed at intervals; a net bodyprovided between said poles; and a shock-absorbing instrument holding ashock-absorbing rope member, wherein said net body has a net bodyturn-down portion formed by turning down_wire members on an edge portionthereof, and a net body intersecting portion in which said wire membersintersect with each other, said net body turn-down portion or said netbody intersecting portion being linked to a linkage member provided onsaid guard fence other than said net body, using said shock-absorbingrope member and said shock-absorbing instrument, so that saidshock-absorbing rope member is allowed to friction slide with respect tosaid shock-absorbing instrument as said net body moves, therebyabsorbing a force of impact applied to said net body, and wherein a loopis formed by curling back said shock-absorbing rope member towarditself, and a portion in which said shock-absorbing rope member isfolded is held by said shock-absorbing instrument, while said loopcouples said linkage member with said shock-absorbing turn-back portionor said net body intersecting portion.
 5. The shock-absorbing device fora net body of a guard fence according to claim 4, wherein saidshock-absorbing turn-back portion or said net body intersecting portionis inserted through said loop.
 6. A shock-absorbing device for a netbody of a guard fence, said guard fence comprising: poles verticallyinstalled at intervals; a net body provided between said poles; and ashock-absorbing instrument holding a shock-absorbing rope member,wherein said net body has a net body turn-down portion formed by turningdown wires members on an edge portion thereof, and a net bodyintersecting portion in which said wires intersect with each other, saidnet body turn-down portion or said net body intersecting portion beinglinked to a linkage member provided on said guard fence other than saidnet body, using said shock-absorbing rope member and saidshock-absorbing instrument, so that said shock-absorbing rope member isallowed to friction slide with respect to said shock-absorbinginstrument as said net body moves, thereby absorbing a force of impactapplied to said net body, and wherein said shock-absorbing rope memberis inserted through mesh patterns of a plurality of said net bodyturn-down portions or said net body intersecting portions, followed byturning back two end portions of said shock-absorbing rope member inopposite directions and allowing respective turn-back portions to befastened to a linkage portion of said guard fence, while said endportions arranged in opposite directions being laid one on top ofanother to form an overlapping portion held by said shock-absorbinginstrument.
 7. A shock-absorbing device for a net body of a guard fence,said guard fence comprising: poles vertically installed at intervals; anet body provided between said poles; and a shock-absorbing instrumentholding a shock-absorbing rope member, wherein said net body has a netbody turn-down portion formed by turning down wire members on an edgeportion thereof, and a net body intersecting portion in which said wiremembers intersect with each other, said net body turn-down portion orsaid net body intersecting portion being linked to a linkage memberprovided on said guard fence other than said net body, using saidshock-absorbing rope member and said shock-absorbing instrument, so thatsaid shock-absorbing rope member is allowed to friction slide withrespect to said shock-absorbing instrument as said net body moves,thereby absorbing a force of impact applied to said net body, andwherein said shock-absorbing rope member is inserted through meshpatterns of a plurality of said net body turn-down portions or said netbody intersecting portions, and wherein said linkage member of saidguard fence is provided with said shock-absorbing instrument,corresponding to two end portions of said shock-absorbing rope member,respectively, thereby allowing said shock-absorbing instrument on bothends to hold said two end portions of said shock-absorbing rope member,respectively.
 8. A shock-absorbing device for a net body of a guardfence, said guard fence comprising: poles vertically installed atintervals; a net body provided between said poles; and a shock-absorbinginstrument holding a shock-absorbing rope member, wherein said net bodyhas a net body turn-down portion formed by turning down wire members onan edge portion thereof, and a net body intersecting portion in whichsaid wire members intersect with each other, said net body turn-downportion or said net body intersecting portion being linked to a linkagemember provided on said guard fence other than said net body, using saidshock-absorbing rope member and said shock-absorbing instrument, so thatsaid shock-absorbing rope member is allowed to friction slide withrespect to said shock-absorbing instrument as said net body moves,thereby absorbing a force of impact applied to said net body, andwherein said linkage member is a pair of linking rope members providedon said guard fence and distant from each other, and a turn-back portionformed by turning back a front end portion of said shock-absorbing ropemember is movably fastened to one and an other linking rope members ofsaid pair of said linking rope members, respectively, and wherein saidnet body turn-back portion or said net body intersecting portion islinked to said front end portion, and an extra length portion isprovided on an other side of said shock-absorbing rope member, saidextra length portions of one and an other shock-absorbing rope membersbeing laid one on top of another to form an overlapping portion held bysaid shock-absorbing instrument.
 9. The shock-absorbing device for a netbody of a guard fence according to claim 1, wherein said linkage memberis said linking rope member provided on said guard fence.
 10. Theshock-absorbing device for a net body of a guard fence according toclaim 8, wherein said linking rope member is a transverse rope memberprovided between said poles.
 11. The shock-absorbing device for a netbody of a guard fence according to claim 9, wherein said linking ropemember is said transverse rope member provided between said poles. 12.The shock-absorbing device for a net body of a guard fence according toclaim 1, wherein a stopper to be fastened to said shock-absorbinginstrument is provided on the end portion of said shock-absorbing ropemember.
 13. The shock-absorbing device for a net body of a guard fenceaccording to claim 2, wherein said linkage member is said linking ropemember provided on said guard fence.
 14. The shock-absorbing device fora net body of a guard fence according to claim 4, wherein said linkagemember is said linking rope member provided on said guard fence.
 15. Theshock-absorbing device for a net body of a guard fence according toclaim 13, wherein said linking rope member is said transverse ropemember provided between said poles.
 16. The shock-absorbing device for anet body of a guard fence according to claim 14, wherein said linkingrope member is said transverse rope member provided between said poles.17. The shock-absorbing device for a net body of a guard fence accordingto claim 4, wherein a stopper to be fastened to said shock-absorbinginstrument is provided on the end portion of said shock-absorbing ropemember.
 18. The shock-absorbing device for a net body of a guard fenceaccording to claim 6, wherein a stopper to be fastened to saidshock-absorbing instrument is provided on the end portion of saidshock-absorbing rope member.
 19. The shock-absorbing device for a netbody of a guard fence according to claim 7, wherein a stopper to befastened to said shock-absorbing instrument is provided on the endportion of said shock-absorbing rope member.
 20. The shock-absorbingdevice for a net body of a guard fence according to claim 8, wherein astopper to be fastened to said shock-absorbing instrument is provided onthe end portion of said shock-absorbing rope member.